iMovie is very particular when it comes to where it’s project is stored, it must be a Mac formatted volume. This is why in the past storing on the local disk was the only option. Most network shares are SMB Windows based, iMovie won’t load a project stored there, unless it is inside a disk image.

  • Open Disk Utility
  • Inside Disk Utility, File -> New Image -> Blank Image...
  • Choose where to save this image, preferably a network drive. Ensure to change the size well above the needed amount for your project, but be careful! This space is used instantly.
  • Once saved, the disk will mount on your computer. The disk should be saved as a .dmg on your network share. Double click this file to mount if not mounted.
  • Open iMovie and create a new project, File -> Open Library -> New...
  • Save the project inside the mounted disk. Find it on the side panel of Finder. Now any changes made to this project are saved inside the disk image sitting on the network! Any files imported to iMovie sit on the network. Simply mount the disk image, and double click the .imovielibrary file to open the project.

If you run out of room in your disk image, do the following:

  • Unmount the disk image
  • Open Disk utility
  • From the menu: Images -> Resize...
  • Find your disk image
  • Type a new size
  • Re-mount disk image